Introduction to Active Species

The scavenging experiment results and electron spin resonance analysis demonstrated that h+ and singlet oxygen were the main reactive species in the degradation process.

In addition, the electron spin resonance (ESR) technology was used to further confirm that the main active species during the photocatalytic degradation of TC.

Relevant photochemical mechanisms to generate reactive species were studied by steady state photolysis, fluorescence, and electron paramagnetic resonance spin-trapping techniques.

Electron paramagnetic resonance analysis showed that OH was the dominant reactive species, which increased rapidly with the increase of OA concentration in the range of 0–2 mM.

Combined with density functional theory calculations, the superior catalytic efficiency of CuNi@C for H2 generation results from the synergistic contribution between the massive active species from HCHO decomposition on the Cu sites and the remarkable H2 evolution activity on Ni sites.

Density functional theory (DFT) calculations further reveal that the active species is Fe porphyrin complex [Fe(TPP)]2− and the rate-determining step is the first hydrogenation of N2 via the alternating mechanism on the [Fe0]2- sites.

The superoxide anion radical (O2•−) was identified as the most influential reactive species for dyes degradation.

By trapping experiments, the superoxide anion radicals (O2˙-) as the main active species to enhance photocatalytic efficiency was established.

Optical emission spectroscopy was carried out to understand the reactive species present with and without dye treatment.

The reactive species formed in the gas phase were studied in-situ by the Optical emission spectroscopy technique.

Trapping experiments indicated that •O2− and h+ were the main active species responsible for the organic pollutant degradation, while •OH played a minor role in this process.

The results of the UV-Vis diffuse reflectance spectra, PL spectra, transient photocurrent response, and reactive-species-trapping experiments indicated that the expanding light-harvesting scope, efficient charge separation ability, and large amounts of active species, are the major reasons for the enhancement photocatalytic activity of CsPbBr3-rGO/Bi2WO6 composite.

In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation.

The trapping experiments demonstrated that the superoxide radical (˙O2−) and h+ were the prominent active species in the photocatalytic reaction system, where the effect of ˙O2− was more significant.

HO radicals are the most important reactive species generated during water treatment by non-thermal plasma devices.

Non-thermal plasma activated water can be used for cheap, easy and chemicals-free surface modification of nanoparticles, with all the reactive species originating solely in air and water.

The three-dimensional TiC/C nanowire network increases the specific surface area between the active species and electrolyte and electron transport efficiency to yield a specific capacitance of 284.

The excellent electrocatalytic properties are primarily by virtue of the highly specific surface area and porosity of carbon support, uniformly dispersed Ru active species, and rapid reaction kinetics of the interaction between Ru and O.

Free radical trapping experiments indicated that ·O2− and h+ were the main active species, which can also be verified by the detection of electron paramagnetic resonance.

Free radical trapping experiments demonstrated that ·O2− radical, ·OH radical and holes served as active species work together to promote photocatalytic reactions.

The free radical capture and electron spin resonance (ESR) experiments confirmed that h + and ∙ O 2 - were the primary active species in the photocatalytic degradation of MO by V2O5/P-g-C3N4 Z-scheme heterogeneous photocatalytic materials.

The free radical capture experiments of the BOP-24/PMS AO7 degradation system showed that •O2-, h+, •OH, and SO4•- are reactive species.

A Z-scheme photocatalytic mechanism was rationally presented based on active species trapping experiments, the band energy potential, PL, and TPR analysis.

Based on the trapping experiments, e− and •OH were the main active species and a Z-scheme photocatalytic mechanism of In2S3/α-Fe2O3 was proposed, which showed the double advantage of high redox ability and efficient electron-hole pairs separation.

Non-thermal atmospheric-pressure plasma is a rising biomedical therapy that generates a mixed cocktail of reactive species by different mechanisms.

Atmospheric pressure plasma jets (APPJs) can enable large fluxes of reactive species impinging on treated substrates in many applications.

It was also evident in the X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) results that pyridinic N and graphitic N were the main active species for PMS activation.

The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation.

In the BCFe-400/PS system, high-valent iron Fe(IV) was the dominant active species for the oxidation, evidenced by methyl phenyl sulfoxide-based probe tests, Mössbauer spectroscopy, and in situ Raman analyses with kinetic evaluation.

The highly oxidized high-valent iron-oxo (Fe(IV)=O) species was the main reactive species in the FePcF16-O-FePcF16/MWCNTs/H2O2 system.

The synergistic effect of active species between MnO and metallic Ni enables Ni–MnO/N–C composites to motivate-boost catalytic activity, the N–C greatly enhances the conductivity and endows Ni–MnO/N–C composites with large surface area for ORR.

6CuCsNH4PVA exhibited a large surface area, more acid sites, and abundant active species (V4+/VO2+) in the secondary structure of the Keggin structure, consequently offering good catalytic performance.

Patients and Methods We measured the levels of oxidative stress markers in plasma and urine: total antioxidant capacity by FRAP (according to a modified method of Benzie & Strain), thiobarbituric acid reactive species – TBARS (spectrophotometric method), 4-hydroxy-2-nonenal (4-HNE) (OxiSelect™ HNE Adduct Competitive ELISA Kit), 3-nitrotyrosine (3-NT) (OxiSelect™ Nitrotyrosine ELISA Kit) in plasma, and F2-isoprostanes (BIOXYTECH® Urinary 8-epi-Prostaglandin F2α) in the urine of 60 schizophrenic patients (before and after treatment) and in 30 healthy subjects.

As urinary biomarkers, (1) hexanoyl-lysine (HEL), which is a new biomarker of oxidative stress, (2) the total antioxidant capacity (TAC), and (3) 8-hydroxy-2′-deoxyguanosine (8-OHdG), as a product of oxidative modifications to DNA; and the plasma levels of (4) the antioxidant protein superoxide dismutase (SOD), which is the crucial defense again oxygen reactive species, and (5) transferrin and (6) ceruloplasmin, which are biomarkers of iron and copper neurotransmission and oxidant-antioxidant systems.

The ES generated by electrical discharges enables a fast transfer of reactive species from plasma into the liquid for an efficient generation of plasma-activated water.

Reactive species were generated in deionized water by using an atmospheric pressure Ar plasma jet within the controlled ambient gases (air, O2 or N2), which allowed the production of plasma-activated water containing only ROS (e.

The possible degradation mechanism explored via different methods like active species capture experiments, electron spin resonance (ESR) determination as well as the corresponding electrochemical analyses.

Quenching experiments, electron spin resonance (ESR) characterization and free radical fluorescence tests demonstrated hydroxyl radicals (·OH) was the dominant reactive species, and the superiority of intermittent electrolysis mode for RhB degradation.

The co-deposition of Cu within the matrix of the Ni foam increases its intrinsic catalytic activity as evidenced by the enrichment of the Ni surface by electro-active species (catalytic mediators) as well as increasing the dispersion (and thus active surface area) of Ni within the porous foam layer.

The unique double-shelled hollow structure provides the large active surface area with rich exposure spaces for the penetration/diffusion of active species and the heterogeneous interface in Ru-Co oxides benefits the electron transfer, simultaneously accelerating the surface electrochemical reactions during HER process.

Both spectroscopic and electrochemical techniques were used to establish the nature of active species in this catalytic reaction and the active catalyst was found to be K2[Ru O3(OH)2], as well as to explain the possible reaction mechanism.

The possible reaction mechanism was proposed and confirmed by both active species capture tests and electron spin resonance (ESR) determinations.

Furthermore, the in-situ synthesized ZSM-5/cordierite has high ZSM-5 loading, high surface area, high pore volume and hierarchical porosity and thus it is a good catalyst support for active species.

The excellent catalytic activity of the prepared HY-NM could be observed due to its high surface area and large porosity, which facilitates the penetration and interaction of reactant molecules with the catalytic active species.

Among them, single-atom catalysts (SACs) have received increasing interest as promising electrocatalysts owing to their maximum utilization of active species, low-coordination environment, quantum size effect and tunable metal-support interaction.

Phosphoric acid could effectively ameliorate the acidity of catalyst and modulate metal-support-interaction (MSI), then the molybdenum species were sulfided to transform into octahedral MoS2 active species with higher degree of sulfurization and dispersion degree.

Trapping experiments of active species and DMPO spin-trapping ESR experiments further confirmed that the visible light photocatalytic tetracycline degradation by Ag/AgCl@Ti3+-TiO2 mesocrystals were mainly due to the continuous attacks of photo-generated holes, OH and O2− radicals on tetracycline molecules.

The synergistic effect of heterojunction and photo-Fenton in the S3/g-C3N4 degradation system promoted the formation of active species, thereby enhancing the visible-light photocatalytic degradation efficiency of p-Nitrophenol.

The photodegradation studies demonstrate that CPs 1–2 show high-efficiency degradation of MV (Methyl violet), and the mechanism studies demonstrate that the main active species are ⋅OH radicals.

The results indicated that singlet oxygen is used as the main active species in the photocatalytic degradation process of Ta2O5 nanosheets, and it can achieve high-efficiency degradation of RhB under the combined action of several other active species.

Moreover, based on the Mott-Schottky calculations, radical trapping experiments and ESR analysis, hydroxide radicals were identified as the main active species, and an S-scheme charge transfer mechanism was suggested to explain the enhanced photocatalytic activity.

The tests including active species trapping, photoelectrochemistry and photoluminescence firmly evidence that the extraordinary Z-scheme charge transfer manner plays dominated role to this excellent activity, which can accelerate charge carrier separation and retain powerful redox ability of electrons on conduction band of g-C3N4 and holes on valence band of WO3 simultaneously; additionally, porous sheet-like nanostructures and oxygen doping also positively influence the activity via improving light harvesting, providing plentiful active sites, shortening charge carrier migration distance and further facilitating charge carrier separation.

Hydroxyl radicals (•OH) are important reactive species that are photochemically generated through solar irradiation of chromophoric dissolved organic matter (CDOM) in surface waters.

Halide ions (X-, X represents Cl, Br and I) are common anions in natural waters and might be oxidized by reactive species originated from photochemistry of dissolved organic matter (DOM) or inorganic photoactive species.

A trapping experiment indicated that sulfate ions, hydroxyl radicals and holes were the main active species in the photocatalytic reaction system.

The •OH, •O2-, h+ and e- were main active species in the photocatalytic reaction system, which were responsible for pollutant degradation and bacteria inactivation.

In addition, quenching experiments confirmed that three reactive species, including hydroxyl radical, hydrated electron and hydrogen radical, contributed to indole degradation.

Alcohols quenching experiments confirmed that ABTS•+ was the primary reactive species responsible for diclofenac elimination, although FeIVO2+ and carbon-centered radicals (R-O•) also existed in ABTS/Fe(II)/PAA process.

The possible photocatalytic reaction mechanism of BB-60 was also revealed by active species trapping experiments.

Further, a possible photocatalytic reaction mechanism of TC•HCl degradation over N-GNDs/Ag/BiVO4 is discussed via through investigation of the charge carrier migration, active species, and intermediates in the degradation processes.

Radical scavenging experiments revealed that photogenerated holes (h+) and hydroxyl radicals (·OH) were the major reactive species involved in TC photodegradation.

Reactive species scavenging experiments revealed that O2-• it plays a dominant role in photodegradation process.

A possible photocatalytic mechanism was proposed according to the active species determined by trapping experiments.

Moreover, a possible photocatalytic mechanism was proposed based on the active species trapping experiments and electron spin resonance (ESR) tests, verifying that the photogenerated holes (h+) and ⋅O2− radicals were the dominating active species, which followed the Z-scheme reaction mechanism.

In particular, the formation of the catalytically active species is probably the main concern, thus the preactivation is in competition with, or even assumes the role of the rate determining step (rds) of the overall reaction.

) reveal that Nb(ƞ1-OOH) hexaniobate is the dominant active species and both the formation of Nb(ƞ1-OOH) hexaniobate species and oxygen transfer process are rate-determining steps.

Using high-resolution mass spectrometry, 62 different PTMs were identified and relatively quantified in vimentin, actin and tubulin proteins, including 12 enzymatic, 13 oxidative and 2 nitric oxide-derived modifications as well as 35 modifications by carbonylated lipid peroxidation products, thus evidencing the occurrence of a chain reaction with formation of reactive species and the activation of multiple signaling pathways.

The mechanism of enhanced photocatalytic degradation of HQ through the formation of OH radicals as reactive species was evidenced by analyzing the formation of fluorescent active molecules on the addition of terephthalic acid and by high-resolution mass spectrometry.

Radical capture experiments and ESR tests affirmed that WS-1 photocatalyst produced •OH and •O2－active species, which further confirmed the photogenerated carriers were transmitted through the Z-scheme mode in principle.

Zn-VBOB can generate more types of radicals as the degradation active species in comparison of the single Zn or OVs introduced ones in which the mechanism was systematically studied by radical capture experiment and DFT calculation.

The results of the active species capture experiment confirms that ⋅ O 2 − and holes (h+) play major roles in the process of degrading norfloxacin by Ag3PO4/ZnO/C under visible light irradiation.

Herein, we utilized ultrathin two-dimensional (2D) Co-based MOF (Co-MOF) nanosheets as specific precursors for preparing carbon matrix encapsulated dual cobalt active species (Co and CoOx) on the surface of CdS for high-efficient photocatalytic H2 evolution under visible-light irradiation.

Surface reconstruction of non-oxide electrocatalysts for the oxygen evolution reaction (OER) to form “true” active species has been reported; however, the mechanism of the in situ surface activation has remained unclear.

Importantly, the electron transfer from Co9S8 to V3S4 occurs at the interface due to the strong electronic coupling effect in Co9S8-V3S4 heterojunction, in which the electron-attracting V3S4 (V2+) optimizes the adsorption of H* active species for hydrogen evolution reaction (HER), while the electron-losing Co9S8 (Co3+) responds to the enhancement of oxygen evolution reaction (OER) activity.

The active species trapping experiments revealed holes in MMNC and superoxide radical anions as the major active species responsible for photodegradation of CR.

Trapping experiments revealed that O2•- was the major reactive species in the photodegradation mechanism.

Body weight, serum glucose, serum nitrite/nitrate, vascular endothelial function, aortic superoxide anion, brains’ oxidative markers (thiobarbituric acid reactive species-TBARS, reduced glutathione-GSH, superoxide dismutase-SOD, and catalase-CAT), mitochondrial enzyme complex (I, II, and IV), inflammatory markers (interleukin-IL-6, IL-10, tumor necrosis factor-TNF-α, and myeloperoxidase-MPO), and acetylcholinesterase activity-AChE were also assessed.

RESULTS STZ treatment produced endothelial dysfunction, impairment of learning and memory, reduction in body weight and serum nitrite/nitrate, and increase in serum glucose, brain oxidative stress (increased brain thiobarbituric acid reactive species and decreased reduced glutathione levels), brain acetylcholinesterase activity and brain myeloperoxidase activity.

Benefitting from the high intrinsic activity of Co0, intimate contact between active species and conductive substrate and the nanostructure which exposes large number of active sites, the Co‐NAs electrode exhibits current density of −2.

The supported and dispersed ultrafine active species for electrocatalytic water oxidation are quite promising for the high intrinsic activity.

Radical trapping experiments suggested that holes and •OH radicals were the dominant reactive species during the photocatalytic process.

The results of active species trapping experiments suggested that superoxide radical (·O2−) played an important role in the reaction.

Radical trapping experiments confirmed •O2−, and •OH radicals were critical active species in the degradation mechanism, which supports the Z-scheme photocatalytic mechanism.

The findings of the trapping experiments confirmed that •O2− and h+ were the important active species in the NO oxidation reaction.

This set up implements advanced oxidation processes (AOPs) by relying on highly active species, specifically ‧OH and O3.

The recent research demonstrates that advanced oxidation processes (AOPs) based on photocatalysts are valuable and this method benefits complete mineralization of organic molecules into nontoxic CO2 and H2O at the atmospheric conditions by generating active species such as hydroxyl radicals (•OH) which can remove even non-biodegradable organic compounds from wastewater.

Photocatalytic reaction mechanism studies exhibited the holes and OH radicals as the main active species in the GQD-0.

Finally, the possible Cu3P-ZSO-CN p-n-n heterojunction photocatalytic reaction mechanism was revealed in detail by the examination of optical properties and capturing experiments of active species.

Based on the scavenging tests, it was revealed that the photogenerated holes (h+), superoxide anions (∙O2–) and hydroxyl radicals (∙OH) were the primary reactive species responsible for the photodegradation process.

During the oxidation process, photogenerated holes (h+) and superoxide radical anions (•O2-) were the main active species.

The results suggest that downregulation of angiotensin converting enzyme 2 (ACE2) with increased activity of the transmembrane protease serine 2 (TMPRSS2) and cathepsin L in SARS-CoV-2 neuroinvasion may result in upregulation of proinflammatory mediators and reactive species that trigger neuroinflammatory response and blood brain barrier disruption.

Twenty-four hours after surgery, the hippocampus and prefrontal cortex were obtained and assayed for levels of blood brain barrier (BBB) permeability, nitrite/nitrate concentration, myeloperoxidase (MPO) activity, thiobarbituric acid reactive species (TBARS) formation and protein carbonyls.

In addition, the composite maintained its activity even after reacting for 20 h, and the charge transfer mechanism between ZnCo2S4 and CN was subject to the S-scheme charge transfer route according to trapping experiments for active species.

We proved the charge transfer mechanism of the Schottky junction and also captured the active species capture experiments.

The free radical quenching experiment showed that sulfate radical (SO4•−) was the main active species in the CoCN10/PMS system.

Moreover, the two Co-MOFs also show good photocatalytic degradation capabilities toward MB/MV dyes under UV irradiation, and the mechanism studies demonstrate that the main active species are ·OH radicals.

Mechanism studies showed that •O2− and h+ were the main active species in the catalytic process.

Additionally, the ·O2- and h+ radicals are the main active species in the degradation of RhB.